In his message to state Republicans, Paul emphasized the need to broaden the party so that it can pull together a winning coalition, according to the Portland Press Herald.

Paul said he had made no final decision about a presidential run. He was focused for now on helping the GOP win Senate races and expanding the party. "The Republican Party's got to be bigger for us to win more races."

"I won my primary with 64 percent of the vote, and since then, have worked with my senior senator in my state [Senate Minority Leader Mitch McConnell] to really try to forge a relationship where we're a bigger, stronger party," Paul said.

The senator said Republicans do not need to agree on every position. "We're a big political party. There's room for not-entire agreement on every issue."

Paul said he "wholeheartedly" endorsed U.S. Sen. Susan Collins of Maine for re-election and shrugged off any differences they might have over National Security Agency surveillance, according to the Press Herald.